1. Field
This disclosure relates to a system for multichannel video content analysis using video multiplexing.
2. Background
Video content analysis (VCA) has become a very important function in a variety of fields, such as retail, health care and security. Traditionally, video surveillance equipment, such as the camera, digital video recorder (DVR) and network video recorder (NVR) have been passive devices. Adding VCA capability to this video equipment facilitates detection of certain features in a video image (e.g., event detection). For example, a VCA-enabled surveillance system can actively monitor a scene to detect an intruder or abandonment of an object, or perform facial recognition, license plate recognition, behavior analysis, object tracking, and intelligent search. In embedded system applications like the DVR and NVR, VCA capability is typically supported by a coprocessor or a VCA processor.
FIG. 1 depicts a system diagram of a typical VCA-enabled DVR, and FIG. 2 depicts a system diagram of a typical VCA-enabled NVR.
A surveillance system may include a plurality of camera devices connected to a DVR or an NVR device. The camera devices may be, for example, an analog video camera (100) or digital camera (200). For example, the analog video camera 100 may output video in CCTV (closed circuit TV) format. The digital camera 200 may be a IP based camera. The ability to actively monitor a multitude of camera scenes at the same time is often paramount to providing optimum security. Therefore, it is very important for VCA-enabled equipments to be able to analyze multiple video channels simultaneously.
Currently in existence are various methods and systems for analyzing multiple video channels. A typical VCA-enabled system, as depicted in FIG. 1 and FIG. 2, includes a VCA processor (110, 210) that receives multiple channel video inputs (10, 20) via a plurality of input lines having respective connectors, and receives configuration inputs (12, 22) and provides the corresponding analysis outputs (15, 25) to a host processor (120, 220). This type of implementation has several disadvantages particularly for embedded system applications. For example, it may be difficult to find or expensive to use a VCA processor chip that includes a large number of video inputs (e.g., a large number of physical input ports for a plurality of connectors such as video cables). For instance, to support VCA on all channels of a 16-channel DVR would require a VCA processor (110, 210) that can support 16 channel video inputs. Commercially available off-the-shelf processor chips either do not support such a large number of video inputs or are unduly expensive. In order to support VCA on such a large number of video inputs, a custom design processor chip may be implemented, but such custom design adds to the cost of the VCA processor. In addition, providing a separate video input for each video to be analyzed (e.g., 16 video inputs, each video input comprising a connector having multiple pins for transmitting a video associated with an individual camera) requires a significant amount of input terminals to the VCA processor, increasing cost further. Furthermore, the inability to use commercially available off-the-shelf processor chip makes the added manufacturing costs for the VCA function cost prohibitive for many applications.